Locks have been developed to meet a wide variety of needs. The most common type of lock use inner and outer cylinders with tumblers which, when moved to the correct position, allow the inner cylinder to rotate within the outer cylinder. The type of key utilized in such a lock is cut so that when the key is placed within the lock the tumblers are moved to their release position thereby enabling the key to rotate the inner cylinder. This type of locking and release mechanism may be referred to as a mechanical lock since the tumblers are physically moved by the shape of the key.
While the mechanical lock is the most common used in today's society it has several distinct disadvantages. First, anyone gaining access to another's key can have it copied within a matter of minutes at any local locksmith or other store having such a service. This is an even more severe problem with motels and businesses wherein a prior patron or ex-employee can have a key copied so as to enable him to enter at some later time. A second disadvantage of the standard mechanical lock is the ability of individuals, with little training or expertise, to learn how to pick these locks with little or no difficulty. Picking tools and instructions are available from most locksmith supply shops, and in most the purchaser need not even identify himself.
In an attempt to overcome these difficulties many types of magnetic locks were developed. These locks would use magnets as tumblers and also place magnets instead of ridges and indents within the key. Thus, one seeking to copy the key would first have to test it in order to determine the positions of the various magnets before a duplicate could be constructed. Alternately, in order to pick the lock one would have to utilize a device for detecting the presence and positions of the magnet tumblers. While such devices clearly aided in preventing unwanted individuals from entering the premises or other secured area several shortcomings were also encountered.
From a practical point of view, probably the most serious shortcoming or magnetic locks was the fact the keys which were used clearly stood out as being different since they did not utilize standard mechanical locking means. Thus, one obtaining such a key would clearly notice that there was a different locking mechanism and would either go to the additional difficulty of creating a duplicate by detecting where the magnets were placed or else would simply seek other access to the premises or other secured area. In addition, since the tumblers themselves were actually magnets an individual seeing the key or being suspicious that the lock was in someway different could easily test for the magnets and with little difficulty develop the correct combination of magnets in a key-like structure to open the lock.
It was with an awareness of these difficulties that I began the development which eventually led to the subject invention. One of the concepts which led to the development of one of the features of this invention involved the dual use of magnetic tumblers to both lock and unlock the inner cylinder. Other features, which will be explained hereafter, were developed primarily in an attempt to produce a lock which could resist most if not all attempts at picking yet were simple enough to be made easily available for virtually all individuals.
It was therefore a main purpose of this invention to provide a locking mechanism which utilized two types of release means, one mechanical and one magnetic.
Another object of this invention was to provide a locking system which appeared like a standard mechanical lock yet included visually undetectable magnetic locking features.
Another object of this invention was to provide a lock which utilized magnetic means which could not be readily detected.
Another object of this invention was to provide a locking system wherein the nonspecific application of magnets to the system would serve to both unlock and lock the inner cylinder.
It was a further object of this invention to provide a locking system which while being highly effective and secure was also inexpensive to manufacture.
Other objects and purposes of the subject invention may become evident from the remainder of this disclosure.
Briefly described, the subject invention discloses a mechanical locking system which utilizes inner and outer cylinders wherein the inner cylinder rotates between a locked and opened position. Tumblers within the cylinders prevent the inner cylinder from turning until the key which is inserted therein moves the tumblers to their predetermined positions, as dictated by the configuration of the key, thereby releasing inner cylinder for rotation and unlocking. In addition, another tumbler is made out of a material which is magnetically attracted but in itself is not a magnet. This tumbler coincides with a visually undiscernable magnet which is placed in the mechanical type key. Full insertion of the key into the lock causes the magnet to be aligned adjacent with the tumbler such that the magnet draws the tumbler to its open position.
Also briefly described, the subject invention has the above described embodiment and includes an additional tumbler which is also made of a material which is attracted to a magnet. However, this second tumbler is biased to an unlocked position and, when the key is fully inserted into the lock, is aligned adjacent to a portion of the key which does not contain a magnet. Thus, insertion of a key which is fully magnetized would draw the second tumbler from its biased unlocked position to a locked position thereby preventing rotation of the inner cylinder.